In general, a washing machine refers to a product that removes pollutants of clothes and bedclothes through emulsification of a detergent, friction of water flow caused by rotations of a pulsator, and impact applied by the pulsator.
The washing machine is divided into a top-loading type in which a washing tub is erected and a drum type in which a washing tub is laid, depending on the shape of the washing tub in which laundry is housed.
When a container of a washing machine is filled up with a liquid detergent easy to dilute and having an excellent emulsification function and a washing command is inputted, the washing machine supplies a preset amount of liquid detergent, and then automatically performs a series of processes including a washing process, a rinsing process, and a spin-drying process.
As a related art of the present invention, Korean Patent Laid-open Publication No. 10-2010-0081214 published on Jul. 14, 2010, has disclosed a washing machine and a sensing method for liquid detergent supply.
Since the conventional washing machine automatically supplies a liquid detergent during a washing process, a user must previously store the liquid detergent in the container before the washing process such that the washing machine does not lack the liquid detergent.
Therefore, the user must frequently check the residual amount of liquid detergent stored in the container, whenever using the washing machine.
Furthermore, since the conventional washing machine includes a plurality of sensors for sensing the residual amount of liquid detergent, the manufacturing cost increases, and a current flowing through the sensors may leak to the container. In this case, the user may get an electric shock.